• replaygain_analysis.h
  • /*
     *  ReplayGainAnalysis - analyzes input samples and give the recommended dB change
     *  Copyright (C) 2001 David Robinson and Glen Sawyer
     *
     *  This library is free software; you can redistribute it and/or
     *  modify it under the terms of the GNU Lesser General Public
     *  License as published by the Free Software Foundation; either
     *  version 2.1 of the License, or (at your option) any later version.
     *
     *  This library is distributed in the hope that it will be useful,
     *  but WITHOUT ANY WARRANTY; without even the implied warranty of
     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     *  Lesser General Public License for more details.
     *
     *  You should have received a copy of the GNU Lesser General Public
     *  License along with this library; if not, write to the Free Software
     *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     *
     *  concept and filter values by David Robinson ([email protected])
     *    -- blame him if you think the idea is flawed
     *  coding by Glen Sawyer ([email protected]) 442 N 700 E, Provo, UT 84606 USA
     *    -- blame him if you think this runs too slowly, or the coding is otherwise flawed
     *  minor cosmetic tweaks to integrate with FLAC by Josh Coalson
     *
     *  For an explanation of the concepts and the basic algorithms involved, go to:
     *    http://www.replaygain.org/
     */
    
    #ifndef GAIN_ANALYSIS_H
    #define GAIN_ANALYSIS_H
    
    #include <stddef.h>
    
    #define GAIN_NOT_ENOUGH_SAMPLES  -24601
    #define GAIN_ANALYSIS_ERROR           0
    #define GAIN_ANALYSIS_OK              1
    
    #define INIT_GAIN_ANALYSIS_ERROR      0
    #define INIT_GAIN_ANALYSIS_OK         1
    
    #ifdef __cplusplus
    extern "C" {
    #endif
    
    typedef float   flac_float_t;         /* Type used for filtering */
    
    extern flac_float_t ReplayGainReferenceLoudness; /* in dB SPL, currently == 89.0 */
    
    int     InitGainAnalysis ( long samplefreq );
    int     ValidGainFrequency ( long samplefreq );
    int     AnalyzeSamples   ( const flac_float_t* left_samples, const flac_float_t* right_samples, size_t num_samples, int num_channels );
    flac_float_t GetTitleGain     ( void );
    flac_float_t GetAlbumGain     ( void );
    
    #ifdef __cplusplus
    }
    #endif
    
    #endif /* GAIN_ANALYSIS_H */